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What is the first indication of skin cancer? An odd-looking mole on the skin. How about cervical cancer? We search for cells that look abnormal. The eyeball, whether aided by microscopes or not, has a critical role to play in medicine, since it feeds information to a brain that is very good at picking out subtle differences.

This is why endoscopes are so useful: they allow doctors to see what would otherwise be hidden. But even then, most endoscopes only show the surface features of organs, while a good diagnosis requires looking at cells that are hidden beneath the surface. This is exactly the problem that a large group of scientists, doctors, and engineers has addressed. The researchers have developed an endoscope that is much better at revealing hidden features.

Water is transparent

In some ways, we should be surprised that we cannot see beneath the surface of our skin. If you’ve ever looked at cells under a microscope, it is really hard to make anything out. You see a couple of thin, barely visible membranes and a few mostly transparent lumps. A cell is mostly water, and most of the light simply passes through it.

Unfortunately, those barely visible parts are enough to change the direction of any light that does pass through, making the next layer blurry. If there were only two layers, you might overcome the blurriness. But there are thousands of layers, each contributing its own distortion, leaving you with a white haze.

At the level of physics, each photon has its direction changed slightly every time it passes through a membrane or bounces off a vesicle. As a result, a reflected photon travels by a random path into the tissue and back out. The randomness of the path is a blessing and a curse: the photon carries some of the path information with it, but interpreting the information is very difficult, and this prevents an image from being reconstructed.

You can see this effect yourself by putting your hand over a bright light. Your fingers will start to glow from the light that passes through the tissue, but the image of the filament is lost by the random path the light takes through your hand.

Labeling photons

But imagine that you could put a tag on each photon—we won’t go into how you do this, because you can’t, though there is a way to label groups of photons. Photons Anna, Bill, and Celine are sent into the tissue, and we time how long they are away for. Bill might return first, followed by Anna, while Celine drags in last having spent her time on a photonic pub crawl.

Now, given the travel time and an idea of the average properties of the material the light traveled through (water, in our case), we can compute the distance that Bill, Anna, and Celine traveled.

An image can be reconstructed by doing that for billions more photons. You carefully keep the illumination conditions the same and measure photons exiting from different locations of tissue.

Once these measurements are combined, an image can be created in various ways. Essentially, image reconstruction requires that all photons have scattered through the same volume, and, therefore, all photon trajectories can be explained by the properties of that volume. A sort of reverse-search of possible volumes reveals the most-likely 3D structure of the volume.

This imaging technique is called optical coherence tomography.

Old new and new news

Optical coherence tomography is old, and it has even been used in endoscopes. But the images tend to be quite blurry. The problem is basically how to squeeze everything into a tube that’s small enough to send inside a human, all while keeping the quality of the optics high.

The issue is that all lenses have imperfections, called aberrations, even if the fabrication is absolutely perfect. Typically, the smaller the lens, the larger the effect of the aberration. In terms of optical coherence tomography, this means that we blur the point where we sample photons. As a result, the quality of the image goes down.

The researchers created a 2D metamaterial that basically consists of rings of pillars. The diameter and spacing of the pillars modifies the optical properties of the surface locally. Effectively, the light emitted from each ring mixes with the light from all the other rings. The mixing can result in constructive interference (a bright spot) or destructive interference (a dark spot). The rings are structured such that at a distance of about 0.5mm, there is a single very tiny spot, just like you would get from a lens. However, this metamaterial lens is flat (like a Fresnel lens) and has been engineered to minimize many of the aberrations.

Searching for alveoli

The metamaterial-lens-equipped endoscope outperformed two other endoscopes that used more traditional optical components (a normal lens and a fiber that focuses light).

After characterizing performance, the researchers imaged a number of tissue samples, including human lung tissue (ex vivo, in this study). They showed that they could obtain relatively clear images of the epidermis, alveoli, cartilage, and blood vessels; they also picked up an abnormality that had been highlighted in the histological images. The key point being that some of these features could not even be seen in images taken with traditional endoscopes.

Some of you may be waiting for a bigger reveal—it’s science and there must be some big discovery. But there isn’t one. I know we like to talk about big breakthroughs and fundamental insights. Science and medicine don’t just advance in big jumps, though. Lots of little steps are more common. And, when you look closely, many of the big jumps involve a run up of lots of little steps.

This endoscope may be one of those little steps. The imaging improvement is not going to revolutionize anything, but it will save lives if it ends up in clinics. And it should allow research scientists to spot tissue abnormalities earlier and understand their development better. All of that makes a difference.

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Chris Lee
Chris writes for Ars Technica's science section. A physicist by day and science writer by night, he specializes in quantum physics and optics. He Lives and works in Eindhoven, the Netherlands. Emailchris.lee@arstechnica.com

This is definitely exciting for picking up early cancer, especially esophageal cancer. The test will be how tolerant it is to real world conditions.

Endoscope lights in busy centres have an annoying tendency to dim over time. For humans it’s not a huge deal; like going from 100% to 50% brightness on your laptop, you can still make things out. But will this imaging still work if it has a lower quality photon source?

Awesome! I wonder how they reconstruct the images and if it could be furthered towards some sort of xray alternative. This sort of technology is extremely promising especially when combined with other forms of nanotech.

Cool! As a camera and lens aficionado have been speculating about the potential use of metamaterials for optics since I first heard of them. Imagine a 10-1000mm zoom that would cover a full frame sensor that was no bigger than a small 50mm normal.

Cool! As a camera and lens aficionado have been speculating about the potential use of metamaterials for optics since I first heard of them. Imagine a 10-1000mm zoom that would cover a full frame sensor that was no bigger than a small 50mm normal.

I think the problem is it sounds like it would be very color-specific. Like you could shoot red-filter black and white or whatever color it's tuned for but no color photography. It would probably also have a T-stop transmission rating like a catadioptric telephoto only maybe worse, and with a many-element zoom much worse. This is an optical system made from very cleverly built neutral density filters.

Having had an endoscopy, I am glad I didn't see what they did it with. I was night night in sleepy land.

That's of course what happened to me too (I clicked off like a light switch out in the hallway), but for some reason I hallucinated/dreamed getting off the gurney, walking into an operating room, and laying on the table. The memory is really vivid. General Anesthesia is a hell of a thing.

The actual procedure is nothing, but the prep is SO grim. Apparently they've changed the formulation again so it's less gross to administer (the liquid I took can best be described as "artificially sweetened death in a little bottle"), but the effect ... yeah, let's not talk about this anymore.

Cool! As a camera and lens aficionado have been speculating about the potential use of metamaterials for optics since I first heard of them. Imagine a 10-1000mm zoom that would cover a full frame sensor that was no bigger than a small 50mm normal.

I think the problem is it sounds like it would be very color-specific. Like you could shoot red-filter black and white or whatever color it's tuned for but no color photography. It would probably also have a T-stop transmission rating like a catadioptric telephoto only maybe worse, and with a many-element zoom much worse. This is an optical system made from very cleverly built neutral density filters.

Colour specificity isn't a big deal, really. When imaging cells, there's rarely any actual colour there to see in the first place! For bulk tissue, it's more of an issue, but I suspect resolution wins over color vision in the end.

Metamaterials are super exciting, and it would be really cool to see them out of the lab and in commercial products. The Next Big Thing (and has been for at least a decade) is a metamaterial lens that can break the diffraction limit. Benchtop optical microscopes that can visualize proteins, yes please.

Having had an endoscopy, I am glad I didn't see what they did it with. I was night night in sleepy land.

That's of course what happened to me too (I clicked off like a light switch out in the hallway), but for some reason I hallucinated/dreamed getting off the gurney, walking into an operating room, and laying on the table. The memory is really vivid. General Anesthesia is a hell of a thing.

The actual procedure is nothing, but the prep is SO grim. Apparently they've changed the formulation again so it's less gross to administer (the liquid I took can best be described as "artificially sweetened death in a little bottle"), but the effect ... yeah, let's not talk about this anymore.

My first surprise was here drink this stuff so you don't miss out on protein over three days. Oops, it's soy. So fast forward two days of 'results' in 45m. At least I knew for certain that soy is a problem. :-P

Having had an endoscopy, I am glad I didn't see what they did it with. I was night night in sleepy land.

Having had both an endoscopy and a colonoscopy whilst fully conscious and watching on a monitor I can say you missed out on a fascinating journey through your insides. It's weird seeing yourself from that perspective but also interesting.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

Good god, I hate finding out so very many of the "simple procedures" that apparently hurt for reasons I don't understand have just been described euphamistically all this time to hide the true horror. Endoscope to "look at your intestines"? Yeah, didn't really have a clear underestanding of why that was so painful. Giant metal teeth from a nightmare bot biting chunks off inside of you? Yeah, now I get it.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

Polyp plucking is usually a good thing. Polyps are nearly always benign or pre-cancerous, so snipping them while they're still polyps prevents potentially REALLY bad birthdays a few years down the road - or possibly an abrupt end to them altogether.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

Good god, I hate finding out so very many of the "simple procedures" that apparently hurt for reasons I don't understand have just been described euphamistically all this time to hide the true horror. Endoscope to "look at your intestines"? Yeah, didn't really have a clear underestanding of why that was so painful. Giant metal teeth from a nightmare bot biting chunks off inside of you? Yeah, now I get it.

It's not painful, even if you're one of those crazy people who want to be awake for it. The stuff you have to do beforehand to clear the pipes is beyond terrible, though.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

Polyp plucking is usually a good thing. Polyps are nearly always benign or pre-cancerous, so snipping them while they're still polyps prevents potentially REALLY bad birthdays a few years down the road - or possibly an abrupt end to them altogether.

Absolutely! As gross as the whole thing is, please everybody, DO IT when it's time.

Having had an endoscopy, I am glad I didn't see what they did it with. I was night night in sleepy land.

That's of course what happened to me too (I clicked off like a light switch out in the hallway), but for some reason I hallucinated/dreamed getting off the gurney, walking into an operating room, and laying on the table. The memory is really vivid. General Anesthesia is a hell of a thing.

The actual procedure is nothing, but the prep is SO grim. Apparently they've changed the formulation again so it's less gross to administer (the liquid I took can best be described as "artificially sweetened death in a little bottle"), but the effect ... yeah, let's not talk about this anymore.

My feeling when watching Dumbledore being forced to drink the Potion of Despair was,"Rowling must have recently had her first colonoscopy."

Cool! As a camera and lens aficionado have been speculating about the potential use of metamaterials for optics since I first heard of them. Imagine a 10-1000mm zoom that would cover a full frame sensor that was no bigger than a small 50mm normal.

I think the problem is it sounds like it would be very color-specific. Like you could shoot red-filter black and white or whatever color it's tuned for but no color photography. It would probably also have a T-stop transmission rating like a catadioptric telephoto only maybe worse, and with a many-element zoom much worse. This is an optical system made from very cleverly built neutral density filters.

The specific application mentioned in the article - optical coherence tomography (OCT) - typically involves an interferometer operating with a laser or a super-luminescent diode (especially in the case of spectral-domain imaging) as its light source; in other words, the light spectrum used in the imaging is very narrowly bounded to begin with. Moreover, the resulting image is not so much a photograph, as it is a volumetric tomogram - indicating tissue opaqueness at each voxel under the narrow wavelength(s) used by the imager. Furthermore, the resulting image is typically distorted due to refractive effects upon the path of a light beam through heterogeneous tissues: it must then be subjected to a "dewarping" through some algorithm that relies upon assumtions about the underlying geometry and optical properties of the tissue(s) being imaged.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

Polyp plucking is usually a good thing. Polyps are nearly always benign or pre-cancerous, so snipping them while they're still polyps prevents potentially REALLY bad birthdays a few years down the road - or possibly an abrupt end to them altogether.

That said, while I would want painkiller, I do NOT want the memory erasing drug. I mean, if it's going to hurt, it's going to hurt. Those moments, that agony, happened whether I remember it or not. All preventing me from remembering it benefits is the doctors.

"Memory erasing drug"? That's not really what's happening. It's simply that you're not home at the time. For my colonoscopy I had the fastest and shortest-acting kind (it lasted about 20 minutes), and other than one very weird hallucination I mentioned above (which I may have had waking up or maybe my brain came up with it to cope with missing time, I don't know), it was like those minutes simply weren't on the clock.

Having had an endoscopy, I am glad I didn't see what they did it with. I was night night in sleepy land.

That's of course what happened to me too (I clicked off like a light switch out in the hallway), but for some reason I hallucinated/dreamed getting off the gurney, walking into an operating room, and laying on the table. The memory is really vivid. General Anesthesia is a hell of a thing.

The actual procedure is nothing, but the prep is SO grim. Apparently they've changed the formulation again so it's less gross to administer (the liquid I took can best be described as "artificially sweetened death in a little bottle"), but the effect ... yeah, let's not talk about this anymore.

My feeling when watching Dumbledore being forced to drink the Potion of Despair was,"Rowling must have recently had her first colonoscopy."

Wow, yeah! They should definitely use "Potion of Despair" as the trade name. Total truth in labeling.

I've kind of been ignoring the topic of the article - better and smaller cameras is a great thing. This is only one of the applications. I wonder if this metamaterial lens tech would work for slightly larger cameras? Endoscopes don't need much range (maybe they look an inch or two from the end of the scope?), I'm thinking this kind of thing won't work for, say, super tiny FPV cams that are focused on infinity.

The specific application mentioned in the article - optical coherence tomography (OCT) - typically involves an interferometer operating with a laser or a super-luminescent diode (especially in the case of spectral-domain imaging) as its light source; in other words, the light spectrum used in the imaging is very narrowly bounded to begin with. Moreover, the resulting image is not so much a photograph, as it is a volumetric tomogram - indicating tissue opaqueness at each voxel under the narrow wavelength(s) used by the imager. Furthermore, the resulting image is typically distorted due to refractive effects upon the path of a light beam through heterogeneous tissues: it must then be subjected to a "dewarping" through some algorithm that relies upon assumptions about the underlying geometry and optical properties of the tissue(s) being imaged.

I think the assumption up the thread was that metamaterial lenses themselves could be used to create photographic lenses. And I don't understand why that wouldn't be true, lenses with diffractive elements or zone plate lenses are already a thing in photographic circles. They would just have some pretty significant limitations.

First of these is that they are, as you and I mentioned, only functional at a specific wavelength being these weird interference-pattern things like array antennae. They might be thought of as having extreme and irreparable chromatic aberration and so would only be functional photo lenses if the unfocusable light was filtered out with a pretty narrow band-pass. Second is that they don't sound like something that passes much light in the first place, so if you wanted a nice, sharp multi-element lens you'd loose a fair amount of light before your image came out the other end. This might be mitigated by the fact that your lens could be much simpler because there's no point in trying to compensate for chromatic aberration. The massive increase in element count to make a zoom might result in something with about the transparency of welding goggles I'm speculating wildly.

Having had an endoscopy, I am glad I didn't see what they did it with. I was night night in sleepy land.

That's of course what happened to me too (I clicked off like a light switch out in the hallway), but for some reason I hallucinated/dreamed getting off the gurney, walking into an operating room, and laying on the table. The memory is really vivid. General Anesthesia is a hell of a thing.

The actual procedure is nothing, but the prep is SO grim. Apparently they've changed the formulation again so it's less gross to administer (the liquid I took can best be described as "artificially sweetened death in a little bottle"), but the effect ... yeah, let's not talk about this anymore.

Both Jeff Foxworthy and Bill Engvall have rather graphically (if hysterically) described the procedure.

What's a bit less revealing is that endoscopy screening for colorectal cancer probably shouldn't be the first option. It's superior at detecting it, but there have been studies which indicate it's not as "safe" as one might be led to believe. No invasive procedure is. Having worked in the medical field for 20 years, it becomes very evident very quickly that even though it can save many lives, some procedures can kill people very, very easily, too. In the end (no puns here, please), there's a risk/benefit factor that needs to be more closely examined. The medical profession is always looking at doing that, but at the same time, routine colonoscopies are a cash cow, and, unfortunately, profit plays a major role in how health care is approached by most in the field.

While the medical profession wants us to think they have a lock on this stuff, the truth is, they don't call it "practicing medicine" for nothing. There's always a learning curve involved. Sometimes, what seems to be a great idea turns out to be less than great. They've already reduced the "every two years" recommendation fro a colonoscopy down to every five, if it's clear because the risks of injury or death during the procedure were TOO MUCH for every two years (Joan Rivers died from such a procedure, by the way). There's talk about making it every ten years, because even at every five years, without any other symptomology (like the non-invasive stool sampling thing showing hidden blood in it), the risks of this procedure may actually cause more general harm overall than individual good (see below for the argument and links there).

If we had a definitive cure for these things that worked all the time for everyone, I'd be more apt to support the idea of invasive procedures as a routine screening method. But because of the expense, the lost productivity, the inconvenience and the risks and the outcomes, invasive procedures should really only ever be done for a more definitive need (positive occult blood test, genetic predisposition, family history, past history, etc.) than just as a routine screening. People shouldn't have things shoved into their bodies unless there's more of an indication there's something to find in there. The risk of dying from the procedure (one in about two or three thousand, with another citing 10 in 16,000+) are possibly HIGHER than dying from the disease (forty or so per HUNDRED thousand).

The health care field has a huge financial stake in continuing colonoscopies as a first method of screening, and it's difficult to find the statistics of deaths and serious injuries from routine colonoscopies. This is juxtaposed against the obvious benefits of the procedure. But given the risks, I'd personally recommend having more justification for having it done than "I turned 50". With much safer screening techniques available to provide that justification, I think it makes more sense to start there, and, if positive, go on to the next step.

After all, you can do that fast, easy, simple, non-invasive test a whole lot more often than the colonoscopy with absolutely no health risks. So if early detection is your thing, it's likely to pick it up faster than waiting years for your next scope up the rear.

As always, if in doubt, ask your doctor.

On the bright side, with techniques in optics like this, at least if you have to have to get scoped, they'll likely be fewer false positives, and false negatives. Once they get this tech out there, that is...

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

Good god, I hate finding out so very many of the "simple procedures" that apparently hurt for reasons I don't understand have just been described euphamistically all this time to hide the true horror. Endoscope to "look at your intestines"? Yeah, didn't really have a clear underestanding of why that was so painful. Giant metal teeth from a nightmare bot biting chunks off inside of you? Yeah, now I get it.

It's not painful, even if you're one of those crazy people who want to be awake for it. The stuff you have to do beforehand to clear the pipes is beyond terrible, though.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

Polyp plucking is usually a good thing. Polyps are nearly always benign or pre-cancerous, so snipping them while they're still polyps prevents potentially REALLY bad birthdays a few years down the road - or possibly an abrupt end to them altogether.

Absolutely! As gross as the whole thing is, please everybody, DO IT when it's time.

The scope procedure is uncomfortable as your colon needs to be inflated to allow proper examination. You will be passing large amounts of gas while having it done and afterwards. The scopes are getting smaller and there's always the option of using a paediatric or oesophagogastric scope if a normal colonoscope is too large.

The prep is unpleasant, though. Unfortunately it's necessary to ensure that everything that needs to be seen _can_ be seen. One thing to keep in mind is that these are "bowel cleansers" rather than laxatives; they're extremely effective if taken correctly and it's important to follow all the instructions, especially about ensuring adequate fluid intake. I read somewhere that putting a little Vaseline around the anus will help prevent soreness, but do it before you take the bowel prep! All that as said, please do not put off having this test if your doctor recommends it; no-one is going to tell you it's a fun way to spend a day, but if there's anything untoward going on in the bowel it's far better to find it early and get it removed ASAP.

FWIW, I work on the admin side of this for part of my day job with the prospect of the doctors I work for seeing an entirely new side to me, i.e. the backside, in the near future. Can't say as I'm looking forward having my colon treated like a blocked sink but the alternative is possibly something unpleasant, even fatal, at some point in the future.

More than a couple of the doctors refer to having scopes at both ends as a "spit-roast", BTW.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

We have come along way from "worst happy 50th birthday present" ie. colonoscopy.

The FIT(Fecal Immunochemical Test)kit works almost equally well and in some parts of the world is the recommended standard as opposed to a thoroughly unpleasant and invasive procedure.

You've got options!

Sort of. But FIT is testing for cancer that's already developed; it's basically looking for blood in the stool. So cancer has already gained a foothold if detected by FIT. A colonoscopy, on the other hand, detects extant cancer, but also pre-cancerous polyps.

An argument can be made that some, many, or even most polyps are benign and don't go on to become cancerous. But removal is very low risk, and may head off worse things to come.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

We have come along way from "worst happy 50th birthday present" ie. colonoscopy.

The FIT(Fecal Immunochemical Test)kit works almost equally well and in some parts of the world is the recommended standard as opposed to a thoroughly unpleasant and invasive procedure.

You've got options!

Sort of. But FIT is testing for cancer that's already developed; it's basically looking for blood in the stool. So cancer has already gained a foothold if detected by FIT. A colonoscopy, on the other hand, detects extant cancer, but also pre-cancerous polyps.

An argument can be made that some, many, or even most polyps are benign and don't go on to become cancerous. But removal is very low risk, and may head off worse things to come.

Hmmm. I guess all of this depends on what your definition of low risk seems to be. I do not consider a perforated intestine to be low risk myself. As with all things ymmv, I submit the following for those who want an non-medically invasive option.

The fecal immunochemical test (FIT) is a screening test for colon cancer. It tests for hidden blood in the stool, which can be an early sign of cancer. FIT only detects human blood from the lower intestines. Medicines and food do not interfere with the test. So it tends to be more accurate and have fewer false positive results than other tests. from NIH

and

Most cases of colon cancer begin with the development of benign intestinal polyps. Benign polyps are relatively common in people over the age of 50, and while most do not cause health problems, some can become cancerous and potentially spread to other parts of the body (metastasize). These finger-like growths protrude into the intestinal cavity (lumen) or the rectum. They can be fragile and bleed intermittently, such as when food waste brushes against them.

The blood released is not usually visible in the stool, but it can be detected with a fecal occult blood test (FOBT) or fecal immunochemical test (FIT). This small amount of blood may be the first and sometimes the only sign of early colon cancer, making the FOBT and FIT valuable screening tools for colorectal (colon and rectal) cancer. Methods for testing include a guaiac-based test (gFOBT), an over-the-counter (OTC) flushable reagent pad, and an immuochemical method (iFOBT or FIT).

It is recommended that testing be performed on at least three stool samples collected on different days. The American Cancer Society has stated that a single test performed at the time of a digital rectal exam in a health practitioner's office is not recommended because it may not be sensitive enough to screen for cancer. The home FOBT or FIT is recommended because the collection of stool on three different days increases the chance of detecting cancer. Furthermore, it is recommended that those who choose this method of colon cancer screening get screened every year.

To pluck polyps out of your intestine. It's the worst "happy 50th birthday" present ever, but very, very effective.

We have come along way from "worst happy 50th birthday present" ie. colonoscopy.

The FIT(Fecal Immunochemical Test)kit works almost equally well and in some parts of the world is the recommended standard as opposed to a thoroughly unpleasant and invasive procedure.

You've got options! My doctor seemed disappointed that he had to write a referral for the FIT instead of a colonoscopy.

edit: for additional comments

Actually no, I don't. The family has a history of polyps, and on my screening, I had two precancerous ones removed. You can be damn sure I have no regrets and will do it again when it's time, even though it's gross as hell.

Let's not play doctor on the internet, people. Not everything is a conspiracy to defraud insurance companies, it may be an earnest attempt to keep you on the planet for longer.

Memory erasing drug"? That's not really what's happening. It's simply that you're not home at the time.

No, it isn't. It's not technically a "memory erasing" drug, it's a "prevent long-term memories from being formed" drug.

You are very much "home" while on it as the reason they use it is so they can direct you to move around to "straighten the path" while the procedure is underway. It's apparently pretty common to get the dosage wrong as I've had 3 procedures using it. One of which I remembered (hazily and unpleasantly) and two I didn't.

For one of the ones I didn't remember, there were two other patients in the prep/recovery room who had just had the same procedure and remembered it. Their description was alarming, considering I was just about to go in to have it.

Memory erasing drug"? That's not really what's happening. It's simply that you're not home at the time.

No, it isn't. It's not technically a "memory erasing" drug, it's a "prevent long-term memories from being formed" drug.

You are very much "home" while on it as the reason they use it is so they can direct you to move around to "straighten the path" while the procedure is underway. It's apparently pretty common to get the dosage wrong as I've had 3 procedures using it. One of which I remembered (hazily and unpleasantly) and two I didn't.

For one of the ones I didn't remember, there were two other patients in the prep/recovery room who had just had the same procedure and remembered it. Their description was alarming, considering I was just about to go in to have it.

I think they use midazolam at our place, but I'm not 100% sure on that or if any other agent is used elsewhere.

Memory erasing drug"? That's not really what's happening. It's simply that you're not home at the time.

No, it isn't. It's not technically a "memory erasing" drug, it's a "prevent long-term memories from being formed" drug.

You are very much "home" while on it as the reason they use it is so they can direct you to move around to "straighten the path" while the procedure is underway. It's apparently pretty common to get the dosage wrong as I've had 3 procedures using it. One of which I remembered (hazily and unpleasantly) and two I didn't.

For one of the ones I didn't remember, there were two other patients in the prep/recovery room who had just had the same procedure and remembered it. Their description was alarming, considering I was just about to go in to have it.

I think they use midazolam at our place, but I'm not 100% sure on that or if any other agent is used elsewhere.

I know ketamine was a component of my last one. Had a nice chat with the anesthesiologist about the developing science around depression there. Then lights out.

Memory erasing drug"? That's not really what's happening. It's simply that you're not home at the time.

No, it isn't. It's not technically a "memory erasing" drug, it's a "prevent long-term memories from being formed" drug.

You are very much "home" while on it as the reason they use it is so they can direct you to move around to "straighten the path" while the procedure is underway. It's apparently pretty common to get the dosage wrong as I've had 3 procedures using it. One of which I remembered (hazily and unpleasantly) and two I didn't.

For one of the ones I didn't remember, there were two other patients in the prep/recovery room who had just had the same procedure and remembered it. Their description was alarming, considering I was just about to go in to have it.

Wow, that's very strange. There is no question that what they gave me is an off switch, there was no responding to commands. Did they give you Ketamine or something? Yow. That stuff is evil.

Why the hell would they direct the patient to move themselves during a colonoscopy? That sounds very, very suspicious to me. Are you sure that actually happened? I noted I had a dreamlike thing where I walked into the operating room, but I have two witnesses who confirmed that did NOT happen, nor did the room look anything like what I described - they actually let me go and look after I told the story.

They used propofol because it's almost instant and wears off quickly with no recovery (unlike the bigtime anesthesia I had for my gall bladder surgery, it took more than a day to feel fully awake after that). Your brain is almost entirely shut down under propofol.

Memory erasing drug"? That's not really what's happening. It's simply that you're not home at the time.

No, it isn't. It's not technically a "memory erasing" drug, it's a "prevent long-term memories from being formed" drug.

You are very much "home" while on it as the reason they use it is so they can direct you to move around to "straighten the path" while the procedure is underway. It's apparently pretty common to get the dosage wrong as I've had 3 procedures using it. One of which I remembered (hazily and unpleasantly) and two I didn't.

For one of the ones I didn't remember, there were two other patients in the prep/recovery room who had just had the same procedure and remembered it. Their description was alarming, considering I was just about to go in to have it.

I think they use midazolam at our place, but I'm not 100% sure on that or if any other agent is used elsewhere.

I know ketamine was a component of my last one. Had a nice chat with the anesthesiologist about the developing science around depression there. Then lights out.

Apparently midazolam and ketamine work similarly, and "inability to form memories" is indeed how they work.

I would not want to have either used on me, I'm in total agreement with you guys on that. Freaking barbarians.

Memory erasing drug"? That's not really what's happening. It's simply that you're not home at the time.

No, it isn't. It's not technically a "memory erasing" drug, it's a "prevent long-term memories from being formed" drug.

You are very much "home" while on it as the reason they use it is so they can direct you to move around to "straighten the path" while the procedure is underway. It's apparently pretty common to get the dosage wrong as I've had 3 procedures using it. One of which I remembered (hazily and unpleasantly) and two I didn't.

For one of the ones I didn't remember, there were two other patients in the prep/recovery room who had just had the same procedure and remembered it. Their description was alarming, considering I was just about to go in to have it.

I think they use midazolam at our place, but I'm not 100% sure on that or if any other agent is used elsewhere.

I know ketamine was a component of my last one. Had a nice chat with the anesthesiologist about the developing science around depression there. Then lights out.

Apparently midazolam and ketamine work similarly, and "inability to form memories" is indeed how they work.

I would not want to have either used on me, I'm in total agreement with you guys on that. Freaking barbarians.

Cool! As a camera and lens aficionado have been speculating about the potential use of metamaterials for optics since I first heard of them. Imagine a 10-1000mm zoom that would cover a full frame sensor that was no bigger than a small 50mm normal.

I think the problem is it sounds like it would be very color-specific. Like you could shoot red-filter black and white or whatever color it's tuned for but no color photography. It would probably also have a T-stop transmission rating like a catadioptric telephoto only maybe worse, and with a many-element zoom much worse. This is an optical system made from very cleverly built neutral density filters.

The specific application mentioned in the article - optical coherence tomography (OCT) - typically involves an interferometer operating with a laser or a super-luminescent diode (especially in the case of spectral-domain imaging) as its light source; in other words, the light spectrum used in the imaging is very narrowly bounded to begin with. Moreover, the resulting image is not so much a photograph, as it is a volumetric tomogram - indicating tissue opaqueness at each voxel under the narrow wavelength(s) used by the imager. Furthermore, the resulting image is typically distorted due to refractive effects upon the path of a light beam through heterogeneous tissues: it must then be subjected to a "dewarping" through some algorithm that relies upon assumtions about the underlying geometry and optical properties of the tissue(s) being imaged.

Just to continue the thought, this is an extremely specific use case far removed from general photography that requires complete control over illumination plus lots of extra information:

Quote:

Now, given the travel time and an idea of the average properties of the material the light travelled through (water, in our case), we can compute the distance that Bill, Anna, and Celine traveled.

An image can be reconstructed by doing that for billions more photons. You carefully keep the illumination conditions the same and measure photons exiting from different locations of tissue.

Not to say metamaterials won't be useful for general camera lenses, but this case does not appear very close to that.

I had a colonoscopy when I was a month shy of 50. The procedure showed a large tumor in the ascending colon that had burrowed deep into the wall of colon. Ten days later I had half of my colon removed, followed by 6 months of chemotherapy, and everything has been great since. Since that time I've had several more colonoscopies. My last colonoscopy showed three more polyps, one of which was sessile, the worst type.

First of all, I have no doubt that the routine colonoscopy saved my life. I had no symptoms at all. Without the procedure the cancer would not have shown until the colon either blocked or ruptured, by which time the cancer would probably have spread to distant organs. I fully recommend that everyone gets screened in some way at the recommended age. Many lives will be saved, one of which might be yours.

Secondly, a colonoscopy procedure really isn't as terrible as many people seem to believe. Yes, it does mean some disruption and a day off work, but the procedure itself is painless and recovery is just a few hours sleeping off the sedation. The preparation is the most disruptive aspect as it is necessary to flush everything out of the intestines, but even that is merely an annoying inconvenience. It's certainly not a procedure to be afraid of or to avoid.